A variety of sensors capable of sensing mechanical movement have been developed. However, if a result sensed by a sensor is transmitted to a monitoring room far away from a detection site, for example when the detection site is more than hundreds of or thousands of meters away from the monitoring room, the detection result is generally required to be transmitted to the monitoring room through an electrical wire.
For example, in an optical cable communication system, a field optical cross-connecting box relatively far away from places of activity of people is generally used to protect intermediate components such as an optical fiber connector, distributor and adapter in the optical cable communication system. In some cases, the cross-connecting box may be opened accidentally, or opened due to technical personnel or engineering personnel forgetting to close it, or opened due to being impacted or stolen. In these unwanted abnormal cases of opening, the optical cross-connecting box cannot provide protection for an optical fiber device therein.
Therefore, there is a need for a sensor which can detect the opening or closure of an optical cross-connecting box at any time, and a detection result is required to be transmitted to a monitoring room far away from the optical cross-connecting box. However, since the optical cross-connecting box is not provided with a power supply device, it is not suitable to use an electric sensor and to transmit a sensed electric signal through an electrical wire.